The inventive concept relates to a method of forming a metal thin film for use in a process of fabricating semiconductor devices and the like.
Physical vapor deposition (PVD), such as sputtering, has conventionally been used to precisely form metal thin films of semiconductor devices and the like. However, metal thin films formed by PVD have poor step coverage. Thus, PVD can not be implemented to meet the recent trend in semiconductor technology toward ultrahigh integration and ultrathin film formation. On the other hand, chemical vapor deposition (CVD) has been considered as a technique for forming metal thin films because films formed by CVD exhibit a high degree of uniformity and excellent step coverage. However, it is difficult to use CVD to form a film having a desired composition ratio and CVD is a process that must be performed at high temperatures. Accordingly, films formed by CVD may adversely affect the electrical properties or lower the capacitance of the resulting device.
To overcome these shortcomings, an atomic layer deposition (ALD) process, in which processing gases are independently supplied, has been developed. However, a dielectric film may be damaged by the chloride used as a metal source gas in the ALD process. In this case, leakage current is increased.